The present invention relates to the field of the manufacture of electronic components and more particularly to manufacturing flexible conductive strips having contact pads thereon.
Many manufacturing processes require the use of masks, film transparencies, or other full scale patterns to control the execution of successive steps in the process. In many cases, the positioning of the product of each step is critical to the location of subsequent steps, or products thereof. It is customary, therefore, to establish registration guides, or alignment marks, at the beginning of a process, which are used to guide the placement of each succeeding step.
For example, in the manufacture of electronic circuit components, the process might begin with a substrate material and include steps such as selective plating, etching, cutting or perforating, insulating overlays, etc. Each step requires a separate registration routine in order to ensure that each part of the process is executed in the correct position, relative to the preceding and succeeding steps. To facilitate this, the designer provides alignment marks, which might be comprised of particular visible features on the substrate, or a series of holes in the substrate, to which the individual masks or steps of the process are aligned. Thus each step, being faithful to the same alignment marks, would be in the correct position relative to each other.
A manufacturer might, for the sake of economy, choose to position many small, identical components on a single large piece of substrate, or master sheet. To do this the masks would have the art for all the parts on the sheet, and would be matched to a single set of alignment marks on the master sheet The larger the number of parts that can be made on a single piece of material, the lower the cost of each individual part.
However, as the size of the master sheet grows, the deviations from perfect registration also increase. Parallax, dimensional stability and uneven tension are among the contributors to such deviations. When the masks and substrate are small, the deviations are correspondingly small. When the master sheet is larger, the designer must accommodate looser tolerances.
In the manufacture of some components, there are many steps in the manufacturing process, only a few of which require very close tolerances, but because of those few steps it becomes necessary to limit the size of the master sheet to one or only a few parts in order to achieve that tolerance, making the parts more costly than they might otherwise have been.
According to principles of the present invention, a first set of alignment marks are provided on a substrate. Using the first set of alignment marks, several electronic components are formed in selected positions on the substrate. The electronic components may be formed in various groups, with a first group being formed using a first mask then, subsequent groups being formed using subsequent masks. Each of the respective masks are aligned with the first set of alignment marks in order to position the electronic components formed using the masks at the desired locations on the substrate.
A second set of alignment marks are produced using the same mask as a set of electronic components that are located on the substrate. Subsequently, when a different set of features is produced, it is positioned using the second set of alignment marks located on the individual parts. Thus, tolerances can be achieved that would normally be possible only in the manufacture of individual parts, while still obtaining the advantages of the economies of scale possible by making many parts on a large sheet. In addition, the subsequent sets of features will be more precisely located with respect to the second set of electronic components than would be possible using the first set of alignment marks.